Warning device for fire protection system

ABSTRACT

This invention relates to an alarm system having a conspicuous warning signal which is automatically exposed to indicate depletion of an exhaustible power supply used to power the alarm. The warning signal remains until sufficient reserve power is restored to the exhaustible power supply and until the alarm is properly fused. The alarm system also includes a device for preventing manipulation of triggering mechanism which would prematurely silence the alarm before the power supply is exhausted, presetting of this triggering mechanism being prevented unless the power supply has a predetermined minimum available power level.

United States Patent [1 1 Gallagher WARNING DEVICE FOR FIRE PROTECTION SYSTEM [75] inventor: Edward L. Gallagher, Capistrano Beach, Calif.

[73] Assignee: A-T-O 1nc., Willoughby, Ohio [22] Filed: Sept. 7, 1971 [21] Appl. No.: 178,247

[52] US. Cl 116/106, 116/114.5, 116/154 [51] Int. Cl. G08b 17/00 [58] Field of Search 116/106, 114.5, 99, 91, 116/109, 154, 102, 4, 5; 185/14, 44; 169/42; 340/219 [56] References Cited UNITED STATES PATENTS 1,910,347 5/1933 Martel 116/106 1,987,590 l/1935 Grison 116/106 1,991,004 2/1935 Thacker, Jr. et a1. 116/106 X 2,871,815 2/1959 Krieger 116/106 2,938,493 5/1960 Pratt 2,999,477 I 9/1961 Pratt et a1. ..-l16/106 [451 Apr. 16, 1974 3,148,658 9/1964 Kaplan 116/106 3,192,890 7/1965 Smith 116/1 14.5 3,552,350 l/197l Ranney.... 116/106 2,554,627 5/1951 Merola 116/154 3,529,567 9/1970 Storm, Jr. 116/102 Primary Examiner-Louis J. Capozi Attorney, Agent, or Firm-Fowler, Knobbe & Martens [5 7] ABSTRACT 25 Claims, 7 Drawing Figures PATENTED 16 I91 3,804,054

SHEET 1 BF 3 INVENTOR. 55/144,917 4. 64144 64156 PATENTEM 151974 3,8 O4, 054

' I SHEET 2 0F 3 WARNING DEVICE FOR FIRE PROTECTION SYSTEM BACKGROUND OF THE INVENTION This invention relates to alarm systems, such as fire or burglar alarms and, more specifically, to apparatus for warning of depleted power levels in exhaustible power supplies of such alarm systems and for preventing premature silencing of the alarm once such alarms have been actuated.

Alarm systems, such as fire and burglar alarm devices, are commonly used in many households and commercial facilities to protect such premises and their occupants from danger. Because of the reliance that building occupants place upon such devices, it is imperative that they be made as simple, foolproof, and-reliable as possible. It is extremely important, for example, that such devices may be left untouched and only casually observed for a period of months or years and may still be expected to operate properly in the event of an emergency. It is common for such alarm systems to be made portable, that is, independent of normal household or facility power, so that they may be conveniently attached to the wall or ceiling of an existing structure without the need for expensive electrical installations. More importantly, this independence of such alarms assures that they may be relied upon to function correctly in the case of an emergency, regardless of failure of the electrical power supplied to the structure. Such systems, therefore, include portable power supplies which, by definition, must be exhaustible, since it isv possible to store only a limited amount of energy within the confines of the alarm system. The more typical of such power supplies are storage batteries, containers holding pressurized gases or liquids, and mechanical energy storage devices such as springs which may be wound to a flexed position and. which will unwind to power the device. Regardless of the type of power supply which is used, it must be capable of producing sufficient power to drive the alarm system for a period of time which is long enough to give adequate wamin g to building occupants of the impending danger.

Each of these exhaustible power supplies is capable of losing all or part of its available power during the stand-by period after the installation of the alarm but before actuation of the alarm. The storage battery, for example, may have reduction of its power potential due to leakage currents caused by humidity or poor electrical isolation of the terminals. Similarly, the pressurized liquid or gas power supply may be reduced in power potential by slow leaks, as through valves which do not adequately seal. Thespring driven power supplies are subject to being partially unwound or only partially wound initially and may, therefore, not have adequate power potential to give the necessary warning signal. It should be noted that, in view of the substantial periods of time which such devices must remain ina standby mode, the failures listed above may occur at a very gradual rate and therefore goundetected by building occupants unless'a thorough inspection of the protection device is undertaken.

Attempts have been made in the prior art to devise warning systems for apprising building occupants of depleted power supplies in such alarm systems. For example, battery driven alarm systems have included audible sounding devices which are actuated by the power supply when the reserve power within the battery is reduced below a predetermined threshold. Such systems, however, depend upon the power of a depletable power supply and, therefore, last only a relatively short period of time. If such a warning occurs when a building is unoccupied, this warning signal may go unnoticed and the alarm system will remain without adequate power while this condition is not apparent on casual observation. Similarly, liquid gas pressure systems have included sight glasses which allow observation of the liquid level within the pressurized container. Such sight glasses, however, must be relatively small to withstand the pressure within the container, and it is therefore necessary to study the sight glasses from a predetermined angle at close range in order to make a determination of the power supply potential. These sight glasses are additionally subject to dirt and dust accumulations from the surrounding air so that they may become totally blocked from casual observance.

Some spring powered alarms of the prior art have iricluded a warning flag which is typically in the form of a lever which rides against the main power supply spring and is hidden from normal veiw when the alarm is sufficiently powered. These flags are movedinto a visible position when the power-supply spring is deflected to a partiallyexhausted position. Such flags and levers, however, often interfere with the operation of the drive spring itself during normal operation, and, if the flag which is exposed to view is stressed, as by accidental blows, substantial damage may be done to the internal workings of the alarm system without the knowledge of building occupants. In addition, since the flag of such warning devices extend outside of the alarm housing, it is awkward and expensive to seal adequately, so that it is impossible to assure that the internal workings of the alarm remain sealed from moisture and dust which may result in reduced reliability. In addition, these warning flag systems generally expose the warning flag to view gradually as the available power within the spring power supply is depleted so that substantial depletion of the power supply may be necessary before a sufficient portion of the warning flag is visible upon casual observation.

In addition to this'inability of the prior art alarms to provide a permanent and conspicuous. warning signal whenever the reserve power supply is depleted beyond a predetermined safe level without allowing the possibility of impeding the internal workings of the alarm by manipulation of the visualwarning signals or their related and cooperative parts and assemblies, prior art alarm systems are generally susceptible to being prematurely silenced. In each of the systems described above, that is the electrical, gas and mechanical alarms, a sensing device, which is sensitive to temperature in the case of a fire alarm or to entry in the case of a burglar alarm, is used to trigger the alarm so that the power from the power supply may be used to drive an audible or visible alarm signal. In the prior art systems, manipulation of the triggering mechanism after the alarm has been initiated can bring a premature, end to the alarm signal. Thus, for example, manipulations of the valve in the gas driven system or manipulations of the electronic heat sensing element of the electrical system could remove the application of the power supply to the alarm mechanism. In the case of mechanically driven alarms, this shortcoming is even more serious. It is common to use which interferes with movement of the drive spring, and to then remove this triggering pin in reaction to temperature changes or unauthorized intrusion into a protected premise. In such systems, manipulation of this lever or pin could bring a premature end to the alarm signal before building occupants had been properly warned. Thus, for example, a building intruder could manually reset the trigger pin or lever in the case of a burglar alarm, or falling debris in a fire could contact the trigger pin or lever in the case of a fire alarm, so that the usefulness of the alarm is inhibited.

SUMMARY OF THE INVENTION The present invention provides a pennanent and conspicuous warning signal whenever the exhaustible power supply of an alarm system is depleted below a predetermined safe level. The invention thereby assures that building occupants, upon casual observance, will readily be apprised of the fact that the alarm is not properly powered and may not be relied upon in the event of danger. This is accomplished without the use of mechanical systems which might impede the internal workings of the alarm device if manually manipulated.

The present invention also provides an alarm system which, once triggered, will produce an alarm signal continuously until the power supply is exhausted, regardless of later manipulation of the triggering mechanism.

In'order to accomplish these results and-to thereby greatly increase the reliability of the alarm system, the present invention prevents the proper'manipulation of the triggering mechanism to preset the alarm unless the power supply exceeds a predetermined minimum power level, and provides a comspicuous warning of the lack of such presetting. More particularly, the preferred embodiment of the present invention utilizes a mechanical, spring-driven alarm system and includes a triggering pin which is spring-biased to a position wherein it does not impede the movement of the main drive spring. This trigger pin is displaced from this position to a position in which it impedes motion of the main drive spring and held in this displaced position by a fuse element. This fuse element, in the case of a fire alarm, melts at a predetermined temperature to allow the trigger pin to move under the action of its spring bias to a position which allows the main drive spring to actuate the alarm.

The present invention also includes a conspicuous warning sign beneath the fuse element, so that if the fuse element is not in place on the fire alarm device, the warning is clearly visible on casual observation. A barrier is responsive to the position of the main drive spring and impedes movement of the triggering pin unless the spring is wound beyond a predetermined position. Thus, it is impossible to depress the triggering pin and to apply the fuse to the alarm device unless the spring is fully wound. This barrier, therefore, serves the purpose of making the warning signal, which the fuse may cover, visible unless the spring is fully wound. The barrier likewise impedes movement of the trigger pin after the alarm has begun sounding, thereby avoiding premature cessation of the alarm.

In addition, the present invention includes a fuse element which incorporates a secondwarning signal in the form of another warning insignia. This insignia is visible when the fuse has become dismantled due to triggering of the alarm, as in the case of response of a fire alarm to elevated temperatures since it is possible for elevated temperatures-to occur in the absence of a fire, the present invention will immediately warn the occupants of a building that the system has been actuated. Thus, even though no one was within the structure to hear the alarm, the occupants are notified to rewind the spring power supply and to replace the actuated fuse.

These and other features of the present invention are best understood through a detailed description of the preferred embodiment shown in the attached figures in which:

FIG. 1 is a perspective view of the overall alarm system of the preferred embodiment;

FIG. 2 is a sectional view taken in the plane of the alarm system shown in FIG. 1, with certain parts out away for ease of illustration of the primary elements of thepresent invention, this Figure showning the spring power supply in the fully exhausted condition;

FIG. 3 is a sectional view similar to FIG. 2, but showing the main drive spring fully wound;

FIG. 4 is a sectional view of the device shown in FIG. 2 taken along lines 4-4, some sectioned parts being shown in elevation for ease of illustration; FIG. 4 showning the main drive spring in the fully exhausted position; i

FIG. 5 is a sectional view taken along the lines 55 of FIG. 3, some sectioned parts being shown in elevation as in FIG. 4, with the main drive spring fully wound;

FIG. 6 is an exploded perspective view of the blocking mechanism which impedes motion of the trigger pin in the preferred embodiment; and

FIG. 7 is a plan view of the warning label located beneath the fuse assembly shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, the overall alarm system of the present invention is shown to include a bell 10 which is used to produce an audible alarm signal and which generally surrounds the alarm apparatus. Centrally located on the alarm system is a fuse assembly 12 which, in the preferred embodiment, is a. temperature sensitive element which responds to changes in the temperature of the surrounding air, such as those caused by a fire in the structure in which the alarm system is located. This fuse assembly 12 is mounted to protrude from the face of the alarm system to increase its exposure to the surrounding air. A series of protruding fingers 14 generally surround the fuse element 12 to protect the fuse element 12 from accidental contact with foreign objects.

The alarm system shown in FIG. 1 is a self-contained unit, having its own power supply, so that it may be conveniently located at the most advantageous position in the facility to be protected, and so that it may be relied upon to operateregardless of the condition of the normal building electrical power supply which is generally susceptible to failure during a fire.

As shown in FIGS. 2 through 5, this self-contained power supply, in the preferred embodiment, comprises a main drive spring 16 which is wound alternately onto a drive reel 18 and a take-up reel 20. This drive spring 16, in its relaxed configuration, is wound clockwise onto the take-up reel 20, as shown in FIGS. 2 and 4. The spring may be wound, as with a winding key (not shown) onto the drive reel 18, as shown in FIGS. 3 and 5. In this configuration, the entire length of the spring is deflected from its clockwise relaxed configuration to a stressed configuration. Therefore, when the reels l8 and are allowed to move, the spring 16, tending to reach its relaxed configuration, will wind from the reel 18 onto the reel 20. It is this action of the main drive spring 16 which is used to drive the audible alarm of the present alarm system.

In particular, the drive reel 18, as shown in FIGS. 2 through 5, is connected to drive a first drive gear 22, and this combination of the reel 18 and gear 22 is rotatably mounted on an axle 24 relative to a base member 26 which is used to support the alarm mechanism.

The first drive gear 22 meshes with a second gear 28 which is rigidly attached to a third gear 30 so that both of the gears 28 and 30 rotate together relative an axle 32 which is mounted on the base 26. The gear 30 in turn drives a fourth gear 34 which is rigidly attached to a striker mechanism 36. This striker mechanism, when rotated, rings the bell 10 through the impact of a pair of weights 38 against the surface of the bell 10. The gear 34 and striker mechanism 36 are rotatably mounted relative base 26 on an axle 40.

It can be seen, therefore, that counter-clockwise rotation of the main drive gear 22, caused by the biasing of the spring 16 which rotates the drive reel 18, will rotate the striker mechanism 36 at a much higher rate than the rotation of the reel 18, since each of the gear combinations, that is, gears 22 and 28 and gears 30 and 34, introduces a gear ratio which increases the rota tional rate of the driven striker mechanism 36.

Referring now, particularly, to FIGS. 4 and 5, a mechanism for triggering the alarm system will be described. The gear 30 includes a protruding tab 42 which, when the gear 30 is at a particular point in its revolution, is directly beneath the fuse assembly 12. A

trigger pin 44 is reciprocally mounted relative the base 26 beneath the fuse assembly 12, and in its lowest position interferes with the rotation of the gear 30 by interferring with the rotational path of the tab 42. This trigger pin 44 is biased by a spring 46 to a position, as shown in FIG. 4, which would remove the trigger pin 44 from the rotational path of the tab 42. As shown in FIG. 5, the fuse assembly 12 is mounted, as by a snapaction socket 48, onto a mounting plate 50 which is in turn mounted on the base member 26 by a pair of screws 52. When this fuse assembly is in position it depresses the trigger pin 44 against the bias of the spring 46 into the path of the tab 42, thereby cocking the alarm.

The fuse assembly 12 includes a heat collecting member 54, which is directly mounted to the socket 48, and a fusable link 56. This fusable link 56, in the preferred embodiment, is attached to the heat collecting member 54 by an eutectic alloy solder which melts at a low temperature (generally below 200 degrees Fahrenheit). When the temperature within the room in which the fire alarm is located rises above the melting temperature of the eutectic alloy, the heat collecting member 54, which has a large surface area relative its low mass, collects heat from the ambient surrounding air and conducts this heat to the eutectic alloy. Once the eutectic alloy solder melts, the fusable link 56 is displaced from its position on the heat collecting member 54 by the trigger pin 44 acting under the bias of the spring 46, so that the trigger pin 44 moves out of the path of the tab 42 allowing the gear 30 and the remainder of the spring and gear driving mechanism to rotate the striker 36 and thereby sound the audible fire alarm.

Without the inclusion of additional apparatus, however, a later depression of the trigger pin 44 will bring the trigger pin 44 back into the rotational path of the tab 42 and will thereby discontinue the actuation of the alarm system.

In order to prohibit such interference of the trigger pin 44 with the actuation of the alarm system, once the alarm has begun to sound, the present invention includes a gate element or impediment in the form of a lever 58 which is formed integrally with an interferring shield 60, best shown in FIGS. 4 and 5. Rotation of the lever 58 will move the shield 60 into or out of the path of the trigger pin 44 so as to block the trigger pin 44 in the position shown in FIG. 4, thus prohibiting its interference with the rotation of the gear 30.

Referring, particularly, to FIGS. 2, 3 and 6, the

means for controlling rotation of the lever 58 and shield 60 will be described. The lever 58 is rotatably mounted on an axle 62 which is in turn mounted on the base 26 of the alarm system. The lever 58 is free to rotate between a position such as that shown in FIG. 2 in which it blocks movement of the trigger pin 44, and a second position, as shown in FIG. 3, in which it is removed from the reciprocating path of the trigger pin 44. Counter-clockwise rotation of the lever 58, as viewed in FIGS. 2 and 3, is limited by a stop (not shown) which impedes rotation of the lever 58 beyond the location shown inFIG. 2,so that the interferring shield 60 cannot be removed from the path of the trigger pin 44 except by a clockwise rotation of the lever 58.

Such clockwise rotation of the lever 58 is caused by a follower 64 which is rotatably mounted on the axle 62. This follower 64 has a depending surface 65 which abuts a lateral surface 67 of the lever 58, as best shown in FIG. 3, so that clockwise rotation of the follower 64 will bring the surfaces of 65 and 67 into contact and will, thereby, force a clockwise rotation of the lever 58. The follower 64 is biased to rotate in this clockwise manner by a spring 68 which connects the follower 64 to the base 26 of the alarm system. The outer extremity of the follower 64 rides against the spring 16 as it is wound on the take-up reel 20 and is biased by the spring 68 to remain in contact with the surface of the spring 16. The take-up reel 20 includes a depression 70 into which one extremity of the spring 16 is wound. This depression 70 is blocked by the spring 16 when the spring 16 is wound around the take-up reel at least one complete turn, as shown in FIG. 2. However, the depression 70 is exposed, as shown in FIG. 3, when the spring 16 is fully wound onto the drive reel 18, in which condition the alarm is fully powered. The follower 64, under the bias of the spring 68, rotates clockwise into the exposed depression 70 and, through the abuttment of the surfaces 65 and 67 of the follower 64 and lever 58 respectively, causes the interferring shield 60 to rotate to the position shown in FIG. 3. With the shield 60 so removed from the path of the trigger pin 44, manual depression of the trigger pin 44 will cock the alarm. However, once the spring 16 has been unwound slightly from the drive reel 18 onto the take-up reel 20, the extremity of the follower 64 will ride on the surface of the spring 16 out of the depression 70, so that the follower 64 will rotate counter-clockwise to the position shown in FIG. 2. A spring 66 connects the follower 64 to the lever 58 so that this counter-clockwise rotation of the follower 64 about the axle 62 will bias the lever 58 to rotate in a counter-clockwise direction also. Such counter-clockwise rotation of the lever 58 will bring the interferring shield 60 into the path of the trigger pin 44 and will thereby inhibit depression of the trigger pin 44 and cocking of the alarm as discussed above. The combination of the follower 64 and lever 58 with its interferring shield 60, therefore, impedes the cocking of the alarm apparatus by depression of the trigger pin 44 unless the spring 16 is fully wound onto the drive reel 18 so that the depression 70 on the take-up reel 20 is exposed. It will be appreciated, therefore, that once the trigger pin 44 has been released by the fuse assembly 12, as discussed above, and moves out of the path of the tab 42 on the gear to enable the alarm, the alarm will begin to sound and the follower 64 will immediately ride on the surface of the spring 16 out of the depression 70. The interferring shield 60 will block later depression of the trigger pin 44 which might cause premature silencing of the alarm mechanism.

Referring to FIGS. 4, 5 and 7, the means for producing a conspicuous warning of lack of adequate power in the alarm system will be described. Beneath the fuse assembly 12, a brightly colored warning label 71 is attached to the mounting plate 50 so that it is hidden from view by the fuse assembly 12 when the fuse assembly 12 is properly attached to the mounting plate 50. This label 71 .is conspicuously visible, as shown in FIGS. 4 and 7, when the fuse assembly 12 is not properly positioned on the fire alarm apparatus. As shown in FIG. 7, the warning label, in addition to being conspicuously colored, may bear instructions as to the required fusing of the device.

The triggering pin 44 cannot be depressed sufficiently to allow the snap-action socket 48 to be applied to the mounting plate 50 unless the interferring shield 60 is removed from the path of the trigger pin 44. It is, therefore, impossible to apply the fuse assembly 12 to the fire protection apparatus, and to thereby hide the warning label 71, unless the interferring shield 60 is removed from the path of the trigger pin 44. This occurs only when the main drive spring 16 is fully wound onto the drive reel 18, as discussed above. Therefore, since the warning label 71 is conspicuously visible in the absence of the fuse assembly 12, this warning label 71 acts as an indication that the alarm system does not have adequate power to produce the required minimum alarm signal in the case of an emergency. This signal remains until adequate power is restored, and is not susceptible to manipulation which could damage or interfere with the internal mechanism of the alarm.

The fuse assembly 12 of the present invention, as shown in FIG. 5, additionally includes a second warning label 72 which is disposed beneath the fusable link 56. The label 72 is hidden by the link 56 prior to the melting of the eutectic alloy which holds the fusable link 56 in place on the heat collecting member 54. Once the fuse assembly 12 has enabled the triggering of the alarm system, the fusable link 56 is displaced from its location on the heat collecting member 54 by the reciprocation of the trigger pin 44. This label 72 is, therefore, conspicuously visible once the alarm has been actuated. Like the label 71, thelabel 72 is preferably brightly colored so that it is apparent to the casual observer. The warning label 72 serves to warn that the fire protection system has been triggered,'as by conditions other than the presence of a fire, when no responsible person was in a position to hear the alarm signal. The label 72 will, therefore, warn that the alarm is exhausted and may not be relied upon to respond to a fire.

It can be seen, therefore, that unless the main drive spring 16 is wound above a threshold level exposing the depression 70 in the reel 20 to the follower 64, one of the two warning labels 71 and 72 must be conspicuously visible, so that the condition of the alarm power supply is always determinable by casual observation.

Referring again to FIGS. 2, 3, 4, 5 and 6, it can be seen that, with the lever 58 rotated out of the path of the trigger pin 44, the trigger pin 44 might be depressed sufiiciently to block rotation of the lever 58 by interferring with motion of the interferring shield 60, but not sufficiently to interfere with motion of the tab 42. If this occurs, the follower 64 is allowed to rotate in a counter-clockwise direction relative the lever 58, biasing the spring 66 as the follower 64 moves out of the depression 70 in the reel 20. The spring 66, in this configuration, maintains a counter-clockwise bias on the lever 58, so that, if the trigger pin 44 is released, the interferring shield will immediately move to impedethe path of the trigger pin 44. The bias of the spring 66 is not strong enough, however, to force the interferring shield 60 against the side of the trigger pin 44 hard enough to interfere with normal alarm actuation by the trigger pin 44. The independent rotation of the lever 58 and follower 64 therefore assures that the safety mechanism of the present invention cannot interfere with normal alarm triggering.

It can thus be seen that the configuration of the present invention produces a conspicuous warning signal whenever the alarm is not powered above a predetermined minimum available power level, and, in addition, prohibits depression of the trigger pin 44 and resultant silencing of the alarm, once the alarm has begun sounding.

I claim:

1. An alarm system, comprising: means for producing an alarm signal;

exhaustible power supply means connected to said alarm signal producing means for supplying power for said alarm signal producing means; trigger means connected to said power supply means for selectively interfering with the operation of said power supply means to selectively actuate said power supply to power said alarm signal producing means;

means for sensing the power level in said exhaustible power supply means; and

means responsive to said sensing means and operatively connected to said trigger means for preventing said trigger means from interfering with operation of said power supply means in response to a predetermined power level in said exhaustible power supply means.

2. An alarm system as defined in claim 1, additionally comprising a wamingsignal which is conspicuous when said trigger is not preset.

3. An alarm system as defined in claim 1, wherein said exhaustible power supply comprises a spring drive mechanism.

4. An alarm system as defined in claim 3, wherein said trigger is mounted to reciprocate between a first position in whichsaid trigger interferes with movement of said spring drive mechanism and a second position in which said trigger does not interfere with movement of said spring drive mechanism, said trigger being biased toward said second position.

5. An alarm system as defined in claim 4, wherein said preventing means prohibits reciprocation of said trigger to said first position from said second position.

6. An alarm system as defined in claim 4, additionally comprising a fuse assembly positioned to prohibit reciprocation of said trigger from said first position to said second position.

7. An alarm system, comprising: alarm means for producing warning signals; exhaustible power supply means connected to said alarm means for powering said alarm means;

trigger means connected to said power supply means for selectively interfering with the operation of said power supply means to selectively actuate said power supply means to power said alarm means;

means for sensing the power level in said exhaustible power supply means; and

means operatively connected to said trigger means and responsive to said sensing means for inhibiting interference with the operation of said power supply means by said trigger means after said trigger means has actuated said power supply means to power said alarm means and before exhaustion of said exhaustible power supply means.

8. An alarm system as defined in claim 7, wherein said inhibiting means comprises an interferring gate which prevents motion of said trigger means.

9. An alarm system as defined in claim 8, wherein said gate is moveable in response to the power level of said exhaustible power supply.

10. An alarm system as defined in claim 7, wherein said inhibiting means inhibits interference with the operation of said power supply means by said trigger means whenever the power level in said exhaustible power supply means is below a predetermined minimum.

11. An alarm system, comprising means for producing an alarm signal;

means for producing a permanent conspicuous warning signal;

exhaustible power supply means connected to said alarm signal producing means forpowering said alarm signal producing means;

trigger means connected to said power supply means for selectively interfering with the operations of said power supply means to selectively actuate said power supply means to power said alarm means;

- and means responsive to said trigger means for selectively actuating said means for producing a permanent conspicuous warning signal whenever said trigger means has actuated said power supply means to power said alarm.

12. An alarm system as defined in claim 11, wherein said hiding means comprises a fuse assembly which fuse assembly additionally activates said trigger.

13. An alarm system as defined in claim 12, wherein said trigger reciprocates to enable said power supply and wherein said fuse assembly is mountable on said alarm system to hide said warning signal only when said trigger is at a predetermined extremity of its reciprocation.

14. An alarm system as defined in claim 13, additionally comprising an impediment for prohibiting reciprocation of said trigger in response to power levels in said exhaustible power supply below a predetermined level.

15. An alarm system, comprising:

means for producing an alarm signal;

means for selectively actuating said alarm signal producing means; and

a warning signal responsive to said actuating means for indicating prior actuation of said alarm signal producing means.

16. A fuse assembly for an alarm system as defined in claim 15 wherein said warning signal is a label, said label being hidden by said enabling means prior to enabling of said alarm by said enabling means, said label being visible upon enabling of said alarm system by said enabling means.

17. A fuse assembly for an alarm system as defined in claim 15 wherein said enabling means is a heat responsive fuse assembly.

18. An alarm system, comprising:

means for producing an alarm signal;

resilient spring drive means connected to said alarm signal producing means for deflecting to activate said alarm signal producing means;

means for monitoring the deflection of said spring drive means;

a trigger pin mounted for movement on said alarm system for selectively interfering with said spring drive means and thereby selectively deactivating said alarm signal producing means; and

impediment means movably mounted on said alarm system for selectively interfering with the movement of said trigger pin to prohibit said trigger pin from deactivating said alarm signal producing means, said impediment connected to move in response to said monitoring means.

19. An alarm system as defined in claim 18, additionally comprising a pair of reels, said resilient spring drive being wound between said pair of reels, and said monitoring means being responsive to the amount of said resilient spring drive wound onto one of said pair of reels.

20. An alarm system as defined in claim 19, wherein said trigger pin prohibits rotation of a first of said pair of reels.

21. An alarm system, comprising: means for producing an alarm signal; exhaustible power supply means connected to power said alarm signal producing means;

trigger means connected to said power supply means for selectively actuating said power supply means to power said alarm system, said trigger means mounted on said alarm system for movement between a cocked position and an uncocked position and means for producing a conspicuous warning signal when said trigger is in said uncocked position.

22. An alarm system, comprising:

means for producing an alarm signal;

a spring drive mounted on said alarm system for powering said alarm signal producing means;

means for monitoring the deflection of said spring drive;

a trigger pin for selectively actuating said spring drive means by moving from a cocked position to an uncocked position;

a warning label mounted on said alarm system; and

a fuse assembly, said fuse assembly detachably mounted on said alarm system to hide said warning label, said fuse assembly being attachable to said alarm system only when said trigger pin is in said cocked position.

23. An alarm system as defined in claim 22, wherein said conspicuous warning signal producing means comprises:

a trigger pin;

a warning label; and

a fuse assembly, said fuse assembly hiding said label, said fuse assembly being attachable to said alarm system in response to the position of said trigger pin.

24. An alarm system as defined in claim 23, wherein said preventing means comprises a gate selectively positionable between said trigger pin and said spring drive.

25. A fuse assembly for a fire alarm system, comprising:

a base member;

a fuse element;

means for attaching said fuse element to said base member, said means permitting said fuse element to be dislodged from said base member in response to elevated temperatures; and

a warning label mounted on said base member beneath said fuse element, said label being visible only when said fuse element is dislodged from said base member.

' a a: In t 

1. An alarm system, comprising: means for producing an alarm signal; exhaustible power Supply means connected to said alarm signal producing means for supplying power for said alarm signal producing means; trigger means connected to said power supply means for selectively interfering with the operation of said power supply means to selectively actuate said power supply to power said alarm signal producing means; means for sensing the power level in said exhaustible power supply means; and means responsive to said sensing means and operatively connected to said trigger means for preventing said trigger means from interfering with operation of said power supply means in response to a predetermined power level in said exhaustible power supply means.
 2. An alarm system as defined in claim 1, additionally comprising a warning signal which is conspicuous when said trigger is not preset.
 3. An alarm system as defined in claim 1, wherein said exhaustible power supply comprises a spring drive mechanism.
 4. An alarm system as defined in claim 3, wherein said trigger is mounted to reciprocate between a first position in which said trigger interferes with movement of said spring drive mechanism and a second position in which said trigger does not interfere with movement of said spring drive mechanism, said trigger being biased toward said second position.
 5. An alarm system as defined in claim 4, wherein said preventing means prohibits reciprocation of said trigger to said first position from said second position.
 6. An alarm system as defined in claim 4, additionally comprising a fuse assembly positioned to prohibit reciprocation of said trigger from said first position to said second position.
 7. An alarm system, comprising: alarm means for producing warning signals; exhaustible power supply means connected to said alarm means for powering said alarm means; trigger means connected to said power supply means for selectively interfering with the operation of said power supply means to selectively actuate said power supply means to power said alarm means; means for sensing the power level in said exhaustible power supply means; and means operatively connected to said trigger means and responsive to said sensing means for inhibiting interference with the operation of said power supply means by said trigger means after said trigger means has actuated said power supply means to power said alarm means and before exhaustion of said exhaustible power supply means.
 8. An alarm system as defined in claim 7, wherein said inhibiting means comprises an interferring gate which prevents motion of said trigger means.
 9. An alarm system as defined in claim 8, wherein said gate is moveable in response to the power level of said exhaustible power supply.
 10. An alarm system as defined in claim 7, wherein said inhibiting means inhibits interference with the operation of said power supply means by said trigger means whenever the power level in said exhaustible power supply means is below a predetermined minimum.
 11. An alarm system, comprising means for producing an alarm signal; means for producing a permanent conspicuous warning signal; exhaustible power supply means connected to said alarm signal producing means for powering said alarm signal producing means; trigger means connected to said power supply means for selectively interfering with the operations of said power supply means to selectively actuate said power supply means to power said alarm means; and means responsive to said trigger means for selectively actuating said means for producing a permanent conspicuous warning signal whenever said trigger means has actuated said power supply means to power said alarm.
 12. An alarm system as defined in claim 11, wherein said hiding means comprises a fuse assembly which fuse assembly additionally activates said trigger.
 13. An alarm system as defined in claim 12, wherein said trigger reciprocates to enable said power supply and wherein said fuse assembly is mountable on said alarm system To hide said warning signal only when said trigger is at a predetermined extremity of its reciprocation.
 14. An alarm system as defined in claim 13, additionally comprising an impediment for prohibiting reciprocation of said trigger in response to power levels in said exhaustible power supply below a predetermined level.
 15. An alarm system, comprising: means for producing an alarm signal; means for selectively actuating said alarm signal producing means; and a warning signal responsive to said actuating means for indicating prior actuation of said alarm signal producing means.
 16. A fuse assembly for an alarm system as defined in claim 15 wherein said warning signal is a label, said label being hidden by said enabling means prior to enabling of said alarm by said enabling means, said label being visible upon enabling of said alarm system by said enabling means.
 17. A fuse assembly for an alarm system as defined in claim 15 wherein said enabling means is a heat responsive fuse assembly.
 18. An alarm system, comprising: means for producing an alarm signal; resilient spring drive means connected to said alarm signal producing means for deflecting to activate said alarm signal producing means; means for monitoring the deflection of said spring drive means; a trigger pin mounted for movement on said alarm system for selectively interfering with said spring drive means and thereby selectively deactivating said alarm signal producing means; and impediment means movably mounted on said alarm system for selectively interfering with the movement of said trigger pin to prohibit said trigger pin from deactivating said alarm signal producing means, said impediment connected to move in response to said monitoring means.
 19. An alarm system as defined in claim 18, additionally comprising a pair of reels, said resilient spring drive being wound between said pair of reels, and said monitoring means being responsive to the amount of said resilient spring drive wound onto one of said pair of reels.
 20. An alarm system as defined in claim 19, wherein said trigger pin prohibits rotation of a first of said pair of reels.
 21. An alarm system, comprising: means for producing an alarm signal; exhaustible power supply means connected to power said alarm signal producing means; trigger means connected to said power supply means for selectively actuating said power supply means to power said alarm system, said trigger means mounted on said alarm system for movement between a cocked position and an uncocked position and means for producing a conspicuous warning signal when said trigger is in said uncocked position.
 22. An alarm system, comprising: means for producing an alarm signal; a spring drive mounted on said alarm system for powering said alarm signal producing means; means for monitoring the deflection of said spring drive; a trigger pin for selectively actuating said spring drive means by moving from a cocked position to an uncocked position; a warning label mounted on said alarm system; and a fuse assembly, said fuse assembly detachably mounted on said alarm system to hide said warning label, said fuse assembly being attachable to said alarm system only when said trigger pin is in said cocked position.
 23. An alarm system as defined in claim 22, wherein said conspicuous warning signal producing means comprises: a trigger pin; a warning label; and a fuse assembly, said fuse assembly hiding said label, said fuse assembly being attachable to said alarm system in response to the position of said trigger pin.
 24. An alarm system as defined in claim 23, wherein said preventing means comprises a gate selectively positionable between said trigger pin and said spring drive.
 25. A fuse assembly for a fire alarm system, comprising: a base member; a fuse element; means for attaching said fuse element to said base member, said means permitting saId fuse element to be dislodged from said base member in response to elevated temperatures; and a warning label mounted on said base member beneath said fuse element, said label being visible only when said fuse element is dislodged from said base member. 